PATHOMORPHOLOGICAL AND MOLECULAR STUDIES OF CANINE TRANSMISSIBLE VENEREAL TUMOR
| dc.contributor.advisor | SAMATHA, V(MAJOR) | |
| dc.contributor.advisor | RAMA DEVI, V | |
| dc.contributor.advisor | RAVI KUMAR, P | |
| dc.contributor.author | YASHASWI, YALAVARTHI | |
| dc.date.accessioned | 2023-04-16T05:17:16Z | |
| dc.date.available | 2023-04-16T05:17:16Z | |
| dc.date.issued | 2022-06 | |
| dc.description | THESES | en_US |
| dc.description.abstract | In the present study, a total of 72 dogs were suspected for canine TVT based on history and clinical signs. Samples from all the suspected cases were collected from the Veterinary Clinical Complex, NTR College of Veterinary Science, Gannavaram, Veterinary polyclinics, private pet clinics and animal birth control centres present in the coastal districts of Andhra Pradesh. Canine TVT was diagnosed in 68 dogs based on cytology, histopathology, histochemistry, IHC, transmission electron microscopy and molecular studies with an overall occurrence of 94.4%. Canine TVT in dogs was recorded in six coastal districts of Andhra Pradesh and the highest occurrence of TVT was found in Guntur district (100%), followed by Krishna (95.4%), East Godavari (91.6%), West Godavari (90.9%), Visakhapatnam (90%) and Prakasam district (87.5%). The occurrence of canine TVT in the present study was highest in the winter (45.6%), followed by the rainy (29.4%) and summer seasons (25%). High occurrence of TVT was seen in dogs aged between 2-4 years (72.1%), dogs aged 4-6 years (16.2%), 6-8 years (8.8%) and >8 years (2.9%). The occurrence of canine TVT was notably higher in female dogs (83.8%) when compared to that of males (16.2%). In the present study, canine TVT was recorded mostly in non-descript dogs when compared to other breeds. The occurrence of tumor location in 57 female dogs was recorded and was highest at the vestibulo-vulval junction (47.4%), vulval lips (19.3%), vulval mucous membrane (17.5%), posterior vagina (15.8%) and six cases revealed tumors on extragenital sites like skin at perineal region in addition to genital tumors. In 11 male dogs, the occurrence of venereal tumor growth was highest at the base of the penis (36.4%), prepuce (36.4%) and on the tip of penis (27.2%). One case showed tumor at extra genital site on the skin in inguinal area in addition to the genital tumor. Most of the TVT suspected dogs showed clinical signs like bloody discharges from genital tracts in both sexes, excessive licking of genitalia, deformation of external genitalia and perineal region due to large tumors. Grossly, TVTs appeared as pink fleshy or dark firm tumors. Tumors on genitalia of both sexes at initial stages appeared as small hyperaemic papules and the progressing tumors appeared nodular, papillary or multilobulated as well as caulifower-like or pedunculated tumors. The predominant cytomorphological pattern of TVT in the present study is the plasmacytic type, followed by the lymphocytic and mixed types. Cytological examination of 68 cases out of 72 suspected dogs revealed canine TVT cells. Canine TVTs were classified into three cytomorphological sub types: plasmacytic (53%), lymphocytic (28%) and mixed (19%), based on the type of tumor cells. Plasmacytic type tumor cells were large ovoid cells with abundant cytoplasm and several clear cytoplasmic vacuoles at cell margins. The cartwheel-shaped nucleus was eccentrically placed and showed one or more prominent nucleoli in the majority of cells. Lymphocytic tumors cells were round cells with scanty cytoplasm. A high nuclear to cytoplasm ratio was evident in the majority of cells. A few cells revealed cytoplasmic and nuclear vacuolation. The nucleus was round and hyperchromatic with coarse chromatin and prominent nucleoli. Mixed type of tumor cells revealed both lymphocytic and plasmacytic tumor cells. Binucleated cells, mitotic figures, neutrophils, erythrocytes and macrophages were observed in many smears. The cytological smears collected from extragenital TVTs in the cutaneous region revealed polymorphonuclear cells and keratinized squamous cells along with TVT cells. In the present study, 68 tissue samples from genital tumors revealed characteristic histopathological features of TVT. The tissue sections revealed a higher number of neoplastic plasma cells and lymphocytes. Histologically, TVT sections were categorised into progressive (35), steady (12) and regressive stages (21). Progressing tumors contained densely packed tumor cells with scanty connective tissue stroma and a significantly higher number of mast cells, mitotic figures and microvessels at the invasion of the tumor. Mild proliferation of fibroblastic cells along with loosely packed round tumor cells were observed in the steady stage of the tumor. The tumors in the regression phase had decreased round tumor cells, decreased mitosis, increased infiltration of TILs and apoptotic cells. Increased proliferation of fibroblasts and increased collagen was evident. Tissue sections (7) from the extra genital tumor growth on the skin had numerous round neoplastic cells in the dermis. The proliferative cellular activity in TVT cells was demonstrated by AgNOR staining in 68 TVT sections. The mean values of AgNOR count were high in progressing tumors (> 7 AgNOR dots) and low in steady (3-7 AgNOR dots) and regression tumors (< 3 AgNOR dots). Immunohistochemical studies of TVT for PCNA and vimentin were carried out. Proliferating cell nuclear antigen (PCNA) showed strong to moderate expression in progressive tumors (61.8%) and in regressing tumors (38.2%) respectively. Vimentin is a specific marker of mesenchymal derivation and immunoreactivity to vimentin was intense in the cytoplasm of more than 90% of the tumor cells. Four TVT positive tissues were subjected to transmission electron microscopy and two revealed plasmacytic, one lymphocytic and one mixed type. Loosely distributed tumor cells and closely packed tumor cells with small protoplasmic microvilli and extensive interdigitation with adjacent cells were observed. Neoplastic lymphocytes and plasma cells were observed and the lymphocytes were round cells with central oval to irregularly round nucleus whereas, plasmacytes were large oval shaped cells with vacuolated cytoplasm and prominent RER with numerous ribosomal clusters. Initial phases of tumor growth revealed elongated cells with elongated nuclei and presence of neovascularization. The presence of more nucleoli and big perichromatin granules were observed, indicating mitotic figures in progressing tumor sections. Regressing tumors revealed collagen between the tumor cells, fibroblast like cells, tissue infiltrating leucocytes and apoptotic cells. Genomic amplification of 22 TVT tissue samples for demonstration of rearrangement of the c-myc gene segment using specific MycS-2 and LINE AS-1 primers revealed an expected product of 550 bp. Based on the cytology, histopathology, histochemistry, immunohistochemistry, electron microscopy and molecular studies, tumors from 68 cases were canine transmissible venereal tumors consisting of lymphocytic, plasmacytic and mixed type of cells at different stages of tumor development. | en_US |
| dc.identifier.uri | https://krishikosh.egranth.ac.in/handle/1/5810196474 | |
| dc.keywords | PATHOMORPHOLOGICAL ; MOLECULAR STUDIES; CANINE; TRANSMISSIBLE; VENEREAL TUMOR | en_US |
| dc.language.iso | English | en_US |
| dc.pages | 173 | en_US |
| dc.publisher | SRI VENKATESWARA VETERINARY UNIVERSITY TIRUPATI - 517 502. (A.P.) INDIA | en_US |
| dc.sub | Veterinary Pathology | en_US |
| dc.theme | PATHOMORPHOLOGICAL AND MOLECULAR STUDIES OF CANINE TRANSMISSIBLE VENEREAL TUMOR | en_US |
| dc.these.type | M.V.Sc. | en_US |
| dc.title | PATHOMORPHOLOGICAL AND MOLECULAR STUDIES OF CANINE TRANSMISSIBLE VENEREAL TUMOR | en_US |
| dc.type | Thesis | en_US |